In U.S. Pat. Nos. 3,878,394 and 3,970,884 there is disclosed a portable x-ray emission source suitable for radiographic uses. Products incorporating the inventions of the aforesaid patents have been manufactured for approximately 20 years by Golden Engineering, Inc. of Centerville, Ind. and sold under the registered work "THE INSPECTOR." These products typically weigh about 20 pounds with battery pack, can be operated on either ac or dc current and are small and light enough to be easily transported from place to place.
As is more fully described in the aforesaid U.S. patents, a portable x-ray emitter of the type to which this patent and the previous patents relate comprises the combination of a battery pack, an inverter for generating a time varying or ac signal quantity, a voltage step-up transformer having primary and secondary windings, a rectifier for converting the secondary winding voltage of the transformer back to dc, a capacitive charge generator, a trigger and a cold-cathode x-ray emitter tube connected to receive the voltage transient generated by the combination of the capacitive charge generator and the trigger. Because the device is operated in a pulsed rather than continuous mode, it is capable of generating a series of x-ray emission pulses, preselectable in number, of high intensity and high penetrating capability with small electrical power dissipation.
We have now found it possible to provide an x-ray emission source of the pulsed emission type which is markedly smaller and lighter than the above-mentioned product, yet suitable for producing high intensity x-ray emission pulses or bursts of high penetration capability. The subject x-ray source is suitable, for example, for the excitation of radiographic image intensifier screens of the type which are commercially available at the present time, using the power available from only a relatively small and lightweight rechargeable battery pack.
Through the design and construction of such a device we have found it possible to increase the utility of portable x-ray emission sources by substantially decreasing the size and weight thereof without sacrificing effectiveness or x-ray emission penetration capability. By way of example we have found it possible to reduce the weight of a portable dc x-ray emitter by about 70% relative to the predecessor product described above without sacrificing penetration capability.